All full size tables have a lock of some kind, From the simplest metal catch on a wagon turntable to elaborate electrical key systems on mainline stuff.
If you put a disc under the center of your table. a sprung wire will locate and lock into holes on the disc to line up with the exit roads and stop any unwanted sideways movement. just release the spring to move to next road where it will stop automatically again.
Sometimes I think laterally, Then I have to get up.
Mark in UK